Previous handle was a pimple on a 2 way screw (no idea what these are called or how it was still holding on) so replaced it with one on 4 bolts on washers for a better grip.
After taking it off it appears that the screw was “sealed” in some sort of wood filler.





Depending on the metal you may be able to just broach it with the bolt itself.
Looking at the pictures I think the wood will break before the bolt cuts into the metal.
Yeah the nuts are cutting into the wood. OP would have to do something different to broach.
The wood is too soft here unfortunately, i tried a little but stopped when the washers started to dig into the wood